Earthquakes are a bit of a mystery to Sounders

The Seattle Sounders have played the San Jose Earthquakes 13 times, so they’ve developed a general idea of what to expect from them.

Except maybe not for their Bay Arena meeting tonight.

San Jose will be without its best-known player: reigning MLS Golden Boot winner Chris Wondolowski, who recorded a hat trick for the United States national team Tuesday in Portland.

And the Quakes are still developing an identity under interim coach Mark Watson, who took over fives games ago (2-3) for Frank Yallop, who had been in charge since before Seattle come into the league.

“(Watson) really hasn’t had the time to put his stamp on the team,” Sounders coach Sigi Schmid said. “I think they’re maybe a little more conservative in terms of going forward than they were under Frank. They were a little more freewheeling going forward with their outside backs getting maybe more involved. But that could be changing as well as he moves forward. Each coach tries to establish a certain pattern, and once you’ve got your structure then you sort of give them more of a free reign within that structure.”

Watson’s efforts to impose his own vision certainly are made more difficult by the absence of four players to international duty. Among those are Wondolowski, who scored an MLS-record 27 goals a season ago, and midfielder Marvin Chavez, who is away with Honduras.

“Wondo is an important part of their team,” Schmid said. “Chaves helps them on the flank areas. They get (Victor) Bernardez back against us I think, so that helps them defensively.”

Seattle’s roster also will be affected by personnel comings and goings.

Schmid revealed Friday that two of the club’s designated players will be held out due to calf injuries: goals leader Obafemi Martins and midfielder Shalrie Joseph.

However, defensive midfielder Osvaldo Alonso is expected to return after missing three straight league games with a quad injury.

“(It has been) frustrating being out like almost six weeks,” Alonso said. “But I’m ready to go Saturday, to step on the field to give the best for my team.”

Alonso’s best is good enough to make him a three-time team MVP, two-time All-Star and a reigning MLS Best XI selection.

“Having him available at midfield makes a big difference,” Schmid said. “? There’s confidence that certainly exists there. Certainly a team like the Miami Heat is going to feel more confident when LeBron James is on the floor. A team like Oklahoma City is going to feel more confident when (Kevin) Durant is on the floor. It’s the same thing: Our team is going to feel more confident when he is on the field.”

And speaking of that field, this match could mark the Sounders’ final appearance at Buck Shaw Stadium, a small multi-purpose stadium on the Santa Clara University campus that the Earthquakes hope to leave in favor of their own soccer-specific stadium next season.

“I’m going to miss Buck Shaw Stadium,” Schmid said. “? I played there as a (UCLA) player — unbelievable as it might sound. I remember coaching (UCLA) there, for sure, as well. It’s seen a lot of improvements: The field’s a lot better than it used to be. They used it for baseball, they also had a football team there – it was pretty thrashed by the time we’d get up there and play on it in October. It was a co-mingling of lines, and a pretty thrashed field. ? (UCLA) lost of playoff game there in the rain where we had balls stop in puddles of water on their way into empty nets.”